Are we getting fatter? According to current research, the answer is a resounding yes. To put it less bluntly, there has been a significant increase in rates of obesity in the past few decades. A study from Memorial University found that rates of obesity in Canada tripled between 1985 and 2011.
Specifically, obesity surged from six to 18 per cent of the population between 1985 and 2011. That period saw in increase of 350 per cent in obesity class 2 and 433 per cent in class 3. These figures relate to calculations of the Body Mass Index (BMI).
BMI is a simple calculation that uses a person’s height and weight. Instead of firing up the formula, it’s simpler to go online to one of the many BMI calculators. Visit the Dietitians of Canada (www.dietitians.ca) to calculate your own. Obesity is defined as a BMI of 30 or higher.
Obesity is further categorized as class 1, 2 or 3 (BMI 30 to 35; 35 to 40; and over 40). Researchers are most concerned about the increases in the higher end of the BMI spectrum in classes 2 and 3. In contrast, a BMI of 18.5 to 24.9 is considered normal.
There are limitations to BMI as an indicator. For example, it is not used for muscle builders, long distance athletes, pregnant women, children and the elderly. This is because the measure does not take into account whether the weight is carried as muscle or fat – it’s just a number. But BMI is still a useful indicator for most people.
We know, then, that we face increasing weight and its many implications for health, but why is it happening in the first place? It would be so nice to say that “x” is the cause and all we need to do is change “x.” Unfortunately, obesity could be the poster child for complex and interwoven causation. Obesity results from the complex interactions of genetic, metabolic, hormonal, psychological, cultural, and socioeconomic factors.
At its most basic, obesity results from an unbalance in energy: weight gain comes from consuming more energy (calories) than are being used. So simple … but there is more to consider. One of the factors at play is an increase in the availability of calories. Since the 1970s people have been increasing their caloric intake, often via high carbohydrate foods (high sugar or starch) and beverages. Add in being surrounded by inexpensive, energy-dense foods often served in over-sized portions and the picture begins to emerge.
For various reasons, this period has seen major changes in the palatability of food (it’s tasting better) because of added sugar, fat and sodium. Overloading on sugar is a related problem, as we have been adding sugar in unexpected places such as pasta sauces, ketchup, canned baked beans, etc. The trend away from home cooking has meant eating out more and choosing ready-to-eat foods, both of which tend to be less healthful and higher in calories than cooking from scratch.
So we consume more calories, but do we exercise more? Nope! Indeed, a study in the American Journal of Medicine found that American women reporting no leisure-time physical activity jumped from 19 up to 52 per cent; for men, the jump was from 11 to 43 per cent.
To learn more about BMI and your own results, talk to your doctor or dietitian who will explain what it means to you, and who can help you devise a plan to make changes that benefit your health.
